The present invention relates to vehicles that do not emit sufficient noise for proximal entities and the like to sense the approach of the vehicle. The term “vehicle” will be used herein to refer to any moving object. Vehicles with which the present invention may be used include non-propelled vehicles and vehicles that are propelled by human power and/or may be motorized. An example of a non-propelled vehicle would be a trailer. Examples of human powered vehicles include bicycles, tricycles, quadracycles, velomobiles, skateboards, rollerblades, or scooters. Examples of motorized vehicles include cars, trucks, motorcycles, boats, personal watercraft, construction equipment, and overhead cranes. Motorized vehicles may be driven by devices such as internal combustion engines, electric motors, compressed air engines, and/or combinations such devices. In addition, certain vehicles are both motorized and can operate partly or wholly under human power.
Currently, the vast majority of powered vehicles employ internal combustion engines. A typical internal combustion engine is clearly audible when operating. A vehicle powered by an internal combustion engine is thus clearly audible to most humans or other animals. The term “proximal entities” will be used herein generally to refer to humans or other animals within the vicinity who are capable of heeding a warning transmitted from a vehicle that is moving or about to move. One important example of a proximal entity is a human pedestrian. The term “proximal entity” can also include machinery capable of reacting to the warning transmitted from such a vehicle.
Many engine technologies that are currently considered alternative, such as electric motors, are quiet and may not be audible to proximal entities. The term “quiet engine” will be used herein to refer to any engine technology that is not clearly audible when operating. Human powered vehicles and vehicles with alternative or quiet engine technologies typically operate at least part of the time without the use of an internal combustion engine. The term “low noise vehicles” will be used herein to refer to vehicles that are capable of movement without the use of an engine, using quiet engine technologies, or under human power. Low noise vehicles moving at higher speeds can sometimes be audible because of the movement of air over the surface of the vehicle. However, at low speeds, low noise vehicles can be essentially silent, providing little audible warning to proximal entities of their approach.
Because low noise vehicles do not make enough noise to provide notice to proximal entities that the vehicle is approaching, low noise vehicles potentially pose a risk to proximal entities. As more vehicles are introduced using alternative engine technologies, the risk to proximal entities of being struck by a low noise vehicle increases.
The need thus exists for systems and methods of warning proximal entities that a low noise vehicle is moving or about to move.